The present invention relates to a blocking-vane pump in which vanes are urged against the contoured surface of a rotor and particularly relates to the distributions of surface area on the rotor and of the vanes in the pump.
Blocking-vane pumps of the type in question here are known. They have a casing within which a rotor is placed in rotation. The circumferential surface of the rotor has at least one control surface which--seen in circumferential direction--is limited on both sides by separating regions. The control surface and the separating regions cooperate with at least one blocking vane which is arranged in a groove in the wall of the stationary casing and is pressed against the control surface. By the rotation of the rotor, chambers of variable volume, which are limited by the blocking vanes, are delimited from each other. By the periodic change in the size of the volumes, a fluid is drawn in and then delivered again at a pressure connection. The known blocking-vane pumps have the disadvantage that, upon the drawing in and delivery of the fluid, either radial forces occur which must be absorbed by a corresponding expensive mounting of the rotor or such blocking-vane pumps, particularly in the case of the two-stroke embodiment, exhibit strong volumetric stream pulsation. By the rotary movement of the rotor, the blocking vanes experience a radial movement which is determined by the contour of the circumferential surface of the rotor. In the case of multi-stroke blocking-vane pumps, the total volumetric stream of the blocking-vane pump is determined by a superimposing of the conveyance function of the pump space formed in each case by a control surface and a vane. Due to this superimposing of partial delivery streams, there results a kinematic volumetric stream pulsation which exhibits delivery stream variations.